# Mechanical Engineer vs Spin Lex

The clearest difference is in-app purchases: Spin Lex at none against Mechanical Engineer's 3. Spin Lex also leads on iOS requirement (15.0 vs 17.6). Mechanical Engineer's advantage is ads (none vs shown). On price, update cadence and device support there is nothing between them.

Both are free to download. Mechanical Engineer sells 3 in-app purchases, starting at $0.99 per month. Spin Lex asks for nothing beyond the download.

Mechanical Engineer ships an update every 2 months, Spin Lex every 3 months. The most recent releases landed on September 26, 2026 and September 16, 2026 respectively.

## The numbers

| Metric | Mechanical Engineer | Spin Lex |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.4 (8 ratings)](https://appshunter.io/ios/app/mechanical-engineer/id327055140/reviews)** | — |
| Number of ratings | **8** | — |
| Positive reviews | 30.8% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 2 months** | Every 3 months |
| Monetization | Free with in-app purchases | — |
| Size | 5 MB | 4 MB |
| Requires iOS | 17.6 | **15.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [Luis David Ortiz Restrepo](https://appshunter.io/developer/1616951514) |

## What reviewers say

### Mechanical Engineer

[App page](https://appshunter.io/ios/app/mechanical-engineer/id327055140)

This app provides over 300 essential mechanical engineering formulas across various domains. It allows users to calculate, save, compare, and share results, aiding in project optimization and decision-making. Users can access a limited number of calculations for free, with a subscription unlocking full functionality.

**Highlights:** Over 300 mechanical engineering formulas, Covers diverse engineering domains, Save and compare formula results, Share calculation outcomes, Intuitive and practical interface, Regular updates based on user input

**Features:** macOS Compatibility

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Subscription | $0.99 | per month |
| Pro Quarterly | $0.99 | per 3 months |
| Pro Yearly | $2.99 | per year |


### Spin Lex

[App page](https://appshunter.io/ios/app/spin-lex-miproceso/id1637769513)

**In-app purchases:** none


## Frequently asked questions

### Is Mechanical Engineer free?

Mechanical Engineer is free to download, with in-app purchases available.

### Is Spin Lex free?

Spin Lex is free to download, with no in-app purchases.

### Do Mechanical Engineer or Spin Lex have ads?

Spin Lex shows ads; Mechanical Engineer does not.

### Which is updated more often, Mechanical Engineer or Spin Lex?

Mechanical Engineer ships an update every 2 months, and Spin Lex every 3 months. Most recently, Mechanical Engineer was updated on September 26, 2026 and Spin Lex on September 16, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*